Stone-polishing wheel



Nov. 29, 1927. 1,651,217

. w. MILNE STONE POLI SHING WHEEL Filed Feb. 20. 1924 19011872207" William JZz'Zn e f /WM m Patented Nov. 29, 1927.

UNITED STATES WILLIAM MILNE, 0F BARRE, VERMONT.

STONE-POLISHING WHEEL.

Application filed February 20, 1924. Serial No. 694,049.

In grinding and polishing stone it is customary to position the surface of the stone substantially horizontally, to spread over the stone surface a mud containing steel shot, emery, or other abrasive material, and then to move over the surface a heavy wheel revolving about a verticalaxis and having 011 its lowerside flanges or scrolls which rub the abrasive material over the surface of the stone. In most cases the area of the Wheel is greater than that of the stone surfaces 1n which event the stones are positioned in a battery with their upper surfaces at the same level and with the spaces therebetween closed with a hard cementitious filler flush with their upper surfaces, a box surrounding the top of the battery to confine the abrasive mud. The upper surfaces of this battery of stones, that is, the aggregate of the surfaces to be ground, or the surface of a single large stone, is ordinarily called the bed.

Various and sundry arrangements of the scrolls on the wheel have been proposed, but experience has taught that formost purposes superior results are attained by arranging the scrolls eccentrically in sectoral sets around the axis of the wheel, the eccentricity of the scrolls causing them to move obliquely across the abrasive on the bed (also to counteract the centrifugal action tending to throw the mud out from beneath the wheel) and the division into sets contributing to the distribution of the abrasive. The present invention relates particularly to wheels of this type which, as heretofore constructed, have not been entirely satisfactory.

One difficulty has been to keep the abrasive from being scraped between the scrolls with too little abrasive acting between the bed and the working surfaces of the scrolls. It is an object of this invention to remedy this defect, to maintain more abrasive mud between the bed and the bottoms of the scrolls, and to produce a more uniform distribution of the mud beneath the wheel.

Another difiiculty experienced in the first rough grinding operation is that the rotating wheel. as it is advanced over the rough surface, is caused to rock about the diameter connecting the leading ends of the peripheral scrolls as a result of said ends striking the higher protuberances of the rough surface, thereby interrupting the continuity of the grinding operation. By the present invention this rocking is minimized by arranging the scrolls so that a greater number of leading ends are presented at the periphery of the wheel and in so distributing these ends as to counteract the rocking tendency.

Still another disadvantage incident to crease the rate of grinding, to equalize the wear on the respective scrolls and the dif- L ferent parts of each scroll, and generally to improve the efficiency of wheels of the aforesaid character.

In one aspect this invention comprises a wheel of the type referred to in which the distance between the scrolls of each set decreases in the direction opposite to the direction of rotation, that is, from the leading to the trailing ends of the scrolls. Owing to the resulting taper of the channels between the scrolls, the abrasive material feeds under the scrolls more effectively and the grinding action is thereby augmented. This taper is preferably effected by decreasing the inward inclination of the eccentric scrolls progressively from the periphery toward the center. Indeed the inclination of the inner scrolls may be reversed so that the trailing ends are farther from the center than the leading ends. Owing to the greater inward inclination-of the outer scrolls, they effectively counteract the outward tendency of the abrasive material near the periphery of the wheel where the centrifugal action is the greatest, whereas the lesser inward inclination of the inner scrolls prevents the abrasive material from accumulating at the center of the wheel, either permitting the centrifugal action to accomplish this result or, when their inclination is reversed, actually impelling the material outwardly.

In another aspect the invention comprises a wheel of the type referred to having two or more sectoral sets of scrolls withthree or more scrolls having their leading'ends distributed approximately uniformly around the periphery of the wheel, and preferabl equidistantly from the center of the whee Ina wheel having two sets of scrolls (which is the usual number) there are preferably four scrolls having their leading ends positioned as aforesaid. In a wheelhaving three sets of scrolls there may be only three outer tween which it is staggered.

scrolls having their leading ends at the-outer periphery of the wheel. Thus, while the numbers may be increased if desired the minimum number of sets is two and the minimum number of outer scrolls is three. These three or more outer scrolls are more effective in knockin off the higher protuberances as the wheel is moved across the bed,

they counteract the aforesaid rocking tendency of the wheel, and they afford a rapid grinding of the marginal portions of the bed so that the center of the bed does not become concave.

In still another aspect the invention involves a unique disposition of the trailing ends of each set of scrolls relatively to the leading ends of the next succeeding set. The trailing end of each scroll terminates in ad- Vance of the leading end of the corres ond- I material proportionate to the linear velocities at different radii.

For the purpose of illustrating the genus of the invention, I have shown two concrete embodiments in the accompanying drawings, in which Fig. 1 is a side elevation of a wheel embodying the invention;

Fig. 2 is a bottom plan of wheel having two sets of scrolls; and

Fig. 3 is a bottom plan of a wheel having three sets of scrolls.

The particular embodiment of the invention shown in Figs. 1 and 2 comprises the usual disk W having means M at the center for attachment to the actuating shaft and having scrolls S fastened to the under side of the disk. The scrolls are divided intotwo sets located on opposite sides of the centor of the wheel respectively The scrolls are mounted eccentrically so that they incline inwardly relatively to the axis of the wheel. The scrolls A and A inclineinwardly to a marked extent, the scrolls B and B to a lesser extent, the scrolls-C and C to a still smaller extent, and the inner scrolls D and D may even incline outwardly to a small extent from their leading to their trailing ends, the wheel rotating in the direction of the arrow in Fig. 2. Thus the channels between the scrolls decrease in width from the leading. to the trailing ends.

Mounted outside the scrolls "A and A, in

the space which is ordinarily wasted, are

scrolls E and E whose leading ends are dis-' abrasive material on the bed, the abrasive material which follows the channels more or less is redistributed in the space between the trailing ends of one set and the leading ends of the next set, part of the material of each channel passing to either side of the scroll of the next succeeding set which follows the channel.

The Wheel shown in Fig. 3 is substantially like that shown in Fig. 2 but has three sets of scrolls instead of two.

In operation the grinding material spreads laterally under the scrolls by virtue of the taper of the channels therebetween, thereby maintaining an adequate layer of abrasive material between the scrolls and the bed, the" grinding, material being thoroughly d stributed in the spaces-F between the trail-' ing-ends of one set and the leadingends of the next set as aforesaid; and the additional scrolls E and E serving to balance the action of the wheel and increase the grinding rateof the outer periphery relative to the center of the wheel.

I claim:

1. A stone polishing wheel having eccentric scrolls arranged in sectoral sets, the leading ends of the scrolls of each set being progressively spaced different distances from the center of the wheel, and the trailing ends of the scrolls of each set also being progressively spaced different distances from the center of the wheel, the distance between the scrolls of each set decreasing in the direction opposite to the direction of rotation. 1

2. A stone polishing wheel having eccentric scrolls arranged in sectoral sets with their centers of curvature near the center of the wheel, the outermost'scrolls inclining toward the center of the wheel in the direction opposite to the direction of rotation, and successive scrolls, progressing toward the center, inclining less and less.

3. A stone polishing wheel having eccentric scrolls arranged in two or more secoral sets with three or more scrolls having their leading ends distributed approximate- 1y uniformly around the periphery of the wheel, the leading ends of the scrolls of each set being progressively spaced different distances from the center of the wheel, and the trailing ends of the scrolls of each set also being progressively spaced different distances from the center of the wheel, scrolls of succeeding sets being circumferentially spaced from each other to form channels between sets which connect points near the center of the wheel with points near the periphery respectively.

4-. A stone polishing wheel having eccentric scrolls arranged intwo or more sectoral sets and having channels extending transversely of the scrolls between the trailing ends of each set and the leading ends of the next succeeding set with a greater number of outer scrolls than sets, said outer scrolls having their leading ends distributed approximately uniformly around the pe riphery of the wheel.

5. A stone polishing wheel having eccentric scrolls arranged in two or more sectoral sets, the leading ends of the scrolls of each set being progressively spaced different distances from the center of the wheel, and the trailing ends of the scrolls of each set also being progressively spaced different distances from the center of the wheel, with a greater number of scrolls than sets, said last-mentioned scrolls having their leading ends distributed around the periphery of the wheel substantially equidista'ntly from the center of the wheel. f

6. A stone polishing wheel having curved scrolls arranged in two or more sectoral sets with their centers off-curvature disposed near the center of the wheel, three or more of the outer scrolls having their leading ends distributed approximately uniformly around the periphery of the wheel, scrolls of succeeding sets being circumferentially spaced from each other to form channels between sets which connect points near the center of the wheel with points near the periphery respectively, and the leading ends of two or more outer scrolls terminating intermediate the ends of the next adjacent scrolls of the same set.

7. A stone polishing wheel having curved scrolls arranged in two or more sectoral sets with their centers of curvature'disposed near the center of the wheel, three or more of the outer scrolls having their leading ends distributed approximately uniformly around the periphery of the wheel, scrolls of succeeding sets being circumferentially spaced from each other to form channels between sets which connect points near the center of the wheel with points near the periphery respectively, and the leading ends of two or more outer. scrolls terminatingin the rear of the leading ends of the nex adjacent: scrolls of the same set.

8. A stone polishing wheel having curved scrolls arranged in sectoral sets with their centers of curvature oifset from the center of the wheel, the trailing ends of each set being radially staggered relatively to the leading ends of the next succeeding set, and the trailing end of each scroll terminating in advance of the leading ends of the scrolls of the next succeeding set between which it is staggered.

9. A stone polishing wheel having eccentric scrolls arranged in sectoral sets, the sets being circumferentially spaced from each other and the spacing increasing from the center outwardly.

10. A stone poli hing wheel having eccentric scrolls arranged in two or more sectoral sets with their centers of curvature oifset from the center of the wheel and with three or more scrolls having their leading ends distributed approximately uniformly around the periphery of the wheel, the distance between the scrolls of each set decreasing in the direction opposite to the direction of rotation, and the trailing end of each scroll terminating in advance of the leading end of the corresponding scroll of the next succeeding set.

11. A stone polishing wheel having eccentric scrolls arranged in two or more sectoral sets with three or more scrolls having their leading ends distributed approximately uniformly around the periphery of the wheel, the distance between the scrolls of each set decreasing in the direction opposite to the direction of rotation, the sets being circumferentially spaced from each other and the spacing being greatest near the periphery of the wheel.

, 12. A stone polishing wheel having curved scrolls arranged in sets with their centers of curvature offset from the center of the wheel but near the center, scrolls of succeeding sets being circumferentially spaced from each other to .form channels between sets which connect points near the center with points near the periphery respectively, and the leading ends of two or more of the outer scrolls being disposed intermediate the opposite ends of the next'adjacent scrolls.

13. A polishing wheel comprising a disc having on its working'face at least three sets of segmental flanges symmetrically arranged in sector-shaped groups, the outermost flanges of each flange group starting at substantially the periphery of the disc and constituting with the included flanges of the group a spaced series of abrasive intake openings, and all of the flanges of each group terminating in substantially the same plane.

14. A polishing Wheel comprising a disc having on its working face at least three sets of segmental flanges symmetrically arranged in sector-shaped groups, the outermost flange of each flange group starting at substantially the periphery of the .disc and constituting with the included flanges of the group a spaced series of abrasive intake openings, and all of the flanges of each group terminating in substantially the same plane.

15. A polishing wheel comprising a disc having on its working face two sets of spaced substantially semi-circular flanges, the outermost flange of each set starting at substantially the periphery of the wheel and terminating at the opposite side of the Wheel and defining with the next innermost flange of each set a pair of oppositely disposed abrasive intake openings, and a pair of shorter feeder flanges starting at substantially opposite points at the periphery of the Wheel intermediate of said intake openings and terminating short of said openin constituting with the included portion of said outermost flanges of the flange sets additional abrasive feeders disposed in baland anced relation to each other and to said outermost flange pair.

16. A polishing wheel comprising a disc having on its working face a plurality of sets of spaced flanges with passageways between the sets extending inwardly from the periphery of the wheel, the outermost flange of certain of said sets starting near the periphery of the wheel and terminating nearer the center of the Wheel than the leading end of the corresponding flange of the next succeeding set, and a shorter feeder flange starting near the periphery of the Wheel intermediate the ends of said outermost. flange, and terminating at the next succeeding passageway.

Signed by me at Barre, Vermont, this 16th day of February, 1924.

WILLIAM M ILNE. 

